MEDICALPSA monitoringHealth Calculator
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PSA Doubling Time (PSADT)

Time for PSA to double. Key prognostic factor after biochemical recurrence. Shorter PSADT suggests more aggressive disease.

Calculate PSA Doubling TimeUse the calculator below to check your health metrics

Why This Health Metric Matters

Why: PSADT guides salvage radiation, ADT timing, and imaging. <3 months: high risk; >12 months: lower risk.

How: PSADT = ln(2) / slope of ln(PSA) vs time. Linear regression on 2+ PSA values.

  • ●<3 mo: high risk
  • ●3-12 mo: intermediate
  • ●>12 mo: lower risk
Sources:AUA BCR Guidelines

Sample Clinical Scenarios — Click to Load

PSA Measurements

Enter at least 2 PSA values with their timing. Most recent measurement should have 0 months ago.

1.
ng/mL
months
2.
ng/mL
months
3.
ng/mL
months

Clinical Context (Optional)

years
months

⚠️For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.

🏥 Health Facts

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Key prognostic factor post-recurrence

— AUA

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Requires 2+ PSA values

— Guidelines

📋 Key Takeaways

  • • PSADT = ln(2) / slope from linear regression of ln(PSA) vs time
  • • PSADT <3 months: 20-fold higher cancer mortality—immediate systemic therapy
  • • Use at least 3 PSA values spanning 6+ months for reliable calculation
  • • Post-surgery vs post-radiation kinetics differ; PSA bounce after brachytherapy is benign
  • • PSADT guides salvage radiation timing, ADT decisions, and imaging frequency

💡 Did You Know?

📊PSADT &lt;3 months is associated with 20-fold higher cancer-specific mortality after biochemical recurrenceSource: Oncology Studies
⏱️PSADT &gt;15 months allows observation; &lt;10 months favors salvage therapy or ADTSource: AUA Guidelines
🔬PSA follows exponential growth—log transform enables linear regression for slope calculationSource: Kinetic Modeling
💊PSMA PET can detect recurrence at very low PSA, potentially before PSADT can be calculatedSource: Imaging Advances
📈Earlier salvage radiation (PSA &lt;0.5) has better outcomes than waiting for more PSADT dataSource: Radiation Oncology
⚕️PSADT during hormone-sensitive phase predicts time to castration resistanceSource: Metastatic Disease

❓ Frequently Asked Questions

How many PSA values do I need for PSADT?

Minimum 2, but 3 or more spanning at least 6 months provides more reliable calculation. More points improve accuracy and R² value.

What if my PSA fluctuates?

Check R² value—if low, calculation may not be reliable. Consider more measurements or lab variation. PSA velocity is an alternative metric.

Is PSADT different after surgery vs radiation?

Yes. Post-surgery, any detectable PSA indicates recurrence. Post-radiation, nadir and bounce phenomena complicate interpretation.

When should I start ADT based on PSADT?

PSADT &lt;10 months generally favors earlier treatment; &gt;15 months may allow observation. Consider symptoms, imaging, and patient preference.

📊 PSADT by the Numbers

3
Min Months (Very High)
10
High Risk Threshold
15
Low Risk Threshold
20x
Mortality Risk (<3mo)

⚠️ Disclaimer: This calculator is for educational purposes only. Prostate cancer management decisions should be made with a urologist or oncologist. PSADT is one factor in comprehensive assessment.

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